I have a problem that I am not able to correct. I have an existing model that runs fine, but when I had to introduce a junction for the second phase of the project, it no longer runs correctly in the post-dev condition. I removed 2 sections and added a junction. Using the energy and forced equal water surfaces equations, I calculated the new runs and it does not produce the expected water surface elevations for the proposed condition, but the existing is good. There 2 sections that are showing an increase for the 2 and 10 year events outside of my project area (further upstream). I have verified that all parameters match between the existing and proposed conditions, therefore, I would expect similar results but no. The proposed condition increases in elevation; whereas, it does not increase in the same location before the junction is inserted.
Additional information – the first section upstream of the junction has non-critcal flow for the existing cond.; whereas, the post-dev cond. has critical flow. Before the junction was added and the 2 sections removed, the post dev had non-critical flow as well.
Any ideas to fix this?